At least two rotating side brushes are required to wash the sides of a vehicle satisfactorily in an automatic car wash. Considering, for example, the left or driver's side of the vehicle, one of the brushes must turn clockwise (when looking down), such that the path of the bristles adjacent the surface of the vehicle is opposite to the direction of the vehicle as it passes the brush. The other brush must turn counter-clockwise (when looking down), such that the path of the bristles adjacent the surface of the vehicle is in the same direction as the path of the vehicle as it passes the brush. Typically, such rotating side brushes are mounted on arms which pivot at points located to the sides of the vehicle.
The clockwise-turning brush does not cause any problems--the fact that the path of the bristles is opposite to that of the path of the vehicle as it passes the brush compensates for the pressure exerted by the brush against the side of the vehicle and does not cause damage thereto. However, the counter-clockwise-turning brush, with its bristles moving in the same direction as the surface of the vehicle when in contact therewith, tends to exert undo pressure on the surface of the vehicle, thereby possibly to cause damage thereto. In the automatic car wash industry, it is said that such a brush tends to "suck" into the side of the vehicle, possibly to do damage to the fenders in the region of the wheel wells and other similarly configured parts.
In order to solve this problem, some car wash equipment manufacturers have tied the two brushes together, for example, by a tie rod. Such a tie rod prevents the counter-clockwise-turning brush from exerting excessive pressure against the side of the vehicle. It is disadvantageous, however, to link car washing brushes together.
Accordingly, it is the principal object of the present invention to provide a rotatable brushing apparatus for washing the generally vertical surfaces of a moving vehicle in an automatic car wash, wherein the direction of motion of the bristles of the brush at the surface of the vehicle is in the same direction as the motion of the vehicle as it passes the brush, and which brush will not damage the vehicle.
It is a further object of the present invention to provide a brush of the aforementioned type that can operate completely independently of any other brushing apparatus in the car wash.
It is a still further object of the present invention to provide such a brushing apparatus that requires no controls other than a biasing spring or a counterweight to urge it into contact with the sides of the vehicle.